Synthesis and characterization study of spinel Co₃O₄ nanoparticles synthesized via the facial co-precipitation route for optoelectronic application

Spinel Co₃O₄ nanoparticles smaller than 10 nm were effectively produced in this study using a Co-precipitation method under optimal conditions. The as-synthesized Co₃O₄ nanoparticles were found to have great purity and a cubic Co₃O₄ phase structure with good crystallinity and crystallite size of approximately 9.3 nm, as determined by X-ray diffraction investigation. The Transmission Electron Microscope and Scanning Electron Microscope definitively verified the spherical nanoparticle structure with high density and consistent orientations. The high-resolution-TEM investigation revealed that the produced spinel Co₃O₄ nanoparticles are single-crystalline and free from observable imperfections. The HR-TEM results indicated that Co₃O₄ nanoparticles exhibit distinct lattice fringes that correspond to the interplanar spacings identified in the XRD investigation. The energy-dispersive X-ray spectroscopy investigation definitively verified the high purity and stoichiometric production of the nanoparticles. The FT-IR spectra of Co₃O₄ nanoparticles showed absorption peaks at v₁ = 540 cm⁻¹ and v₂ = 656 cm⁻¹, confirming the spinel phase structure of the nanoparticles. UV–Vis spectroscopy was utilized to confirm the existence of two distinct band gaps in Co₃O₄ nanoparticles at energy levels of 3.4 eV and 4.21 eV. Obtaining Co₃O₄ nanoparticles smaller than 10 nm with specific properties allows for the development of innovative and effective optoelectronic devices with customized features.